<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Flex Demo 1</title>
  <style>
    /*
      1. 设计好DOM结构
      2. 将父盒子设置为伸缩盒子
     */
    html, body {
      height: 100%;
    }

    .root {
      /* 将父盒子设置为伸缩盒子 */
      display: flex;
      border: 2px solid #ccc;
      height: 100%;
    }

    .sidebar {
      width: 200px;
      background-color: #ff0;
    }

    .content {
      /*width: 300px;*/
      /* ???? */
      flex: 1;
      background-color: #e0e0e0;
    }
  </style>
</head>
<body>
  <div class="root">
    <div class="sidebar">

    </div>
    <div class="content">

    </div>
  </div>
</body>
</html>
